Mark W. Nixon

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The paper describes the aeroelastic analysis of a tiltrotor conaeguration. The 1è5 scale wind tunnel semispan model of the V-22 tiltrotor aircraft is considered. The analysis is performed by means of a multi-body code, based on an original formulation. The diaeerential equilibrium problem is stated in terms of aerst order diaeerential equations. The(More)
This work is focused on the implementation of a general multibody analysis framework for the real-time simulation of complex systems. It is applied to the modeling of the Semi-Articulated Soft-InPlane (SASIP) rotor recently installed and tested on the Wing and Rotor Aeroelastic Testing System (WRATS) at NASA Langley. The aim is to obtain a detailed, yet(More)
The results of a joint NASA/Army/Bell Helicopter Textron wind-tunnel test to assess the potential of Generalized Predictive Control (GPC) for actively controlling the swashplate of tiltrotor aircraft to enhance aeroelastic stability in the airplane mode of flight are presented. GPC is an adaptive time-domain predictive control method that uses a linear(More)
* The results of a joint NASA/Army/Bell Helicopter Textron wind-tunnel test to assess the potential of higher harmonic control (HHC) for reducing vibrations in tiltrotor aircraft operating in the airplane mode of flight, and to evaluate the effectiveness of a Bell-developed HHC algorithm called MAVSS (Multipoint Adaptive Vibration Suppression System) are(More)
  • David J. Piatak, Raymond G. Kvaternik, +4 authors Ross K. Brown
  • 2001
A wind-tunnel investigation of tiltrotor whirl-flutter stability boundaries has been conducted on a 1/5-size semispan tiltrotor model known as the Wing and Rotor Aeroelastic Test System (WRATS) in the NASA-Langley Transonic Dynamics Tunnel as part of a joint NASA/Army/Bell Helicopter Textron, Inc (BHTI) research program. The model was first developed by(More)
A new four-bladed, semi-articulated, soft-inplane rotor system, designed as a candidate for future heavy-lift rotorcraft, was tested at model scale on the Wing and Rotor Aeroelastic Testing System (WRATS), a 1/5-size aeroelastic wind-tunnel model based on the V-22. The experimental investigation included a hover test with the model in helicopter mode(More)
The objective of this investigation is to illustrate a modular approach in the development and validation of sophisticated rotorcraft analytical models within the framework of multibody dynamics simulations. This approach is demonstrated with the development of a stiff-inplane tiltrotor wind-tunnel model using two multibody dynamics analyses. The two(More)
This paper presents the development of two multibody dynamics models to predict the whirl-flutter stability of a stiff-inplane tiltrotor wind-tunnel model and correlates the predictions with experimental data. Comprehensive, multibody-based dynamics analyses of rotorcraft enable modeling and simulation of the rotor system at a high level of detail so that(More)